Lifting-jack.



J. M. HAWKINS, S. E. ADKINS 61; W. 0. CALL.

LIFTING JACK.

APPLICATION FILED MAYB, 1909. 957,333. Patented May 10,1910.

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J. M. HAWKINS, s. E. ADKINS & W. a GALL.

LIFTING JACK. APPLICATION PILEDMAY8, 1909.

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JOHN M. HAWKINS, SILVESTER E. ADKINS, AND WILLIE 0. CALL, OF SPENCER, INDIANA.

LIFTING-JACK.

Specification of Letters Patent.

Patented May 1d, 191M).

Application filed May 8, 1909. Serial No. 494,729.

To all whom it may concern:

Be it known that we, JOHN M. HAWKINS, SILVESTER E. ADKINS, and IVILLm 0. CALL, citizens of the United States, residing at Spencer, in the county of Owen, State of Indiana, have invented certain new and useful Improvements in Lifting-Jacks; and we do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

The invention relates to a lifting device and more particularly to the class of lifting acks.

The primary object of the invention is the provision of a lifting jack in which a movable member is mounted for sliding movement upon a standard and within this movable member are arranged frictional gripping means the same being operated by an eccentric to advance the said member in either direction upon the standard and which will enable an operator to lift a load from the ground in a vertical direction or to exert a pull in a horizontal plane as in stretching a wire for which the device is also adaptable as well as lifting heavy loads or objects.

Another object of the invention is the provision of a lifting jack in which the supporting member mounted upon the standard is advanced in either direction upon the latter by clamping members or grips adapted to alternately grip and slide on the standard so that the said supporting member may lift a heavy load or object as the occasion demands.

A further object of the invention is the provision of a lifting jack which is simple in construction, thoroughly reliable and eflicient in operation and inexpensive in the manufacture.

Vith these and other objects in view, the invention consists in the construction, combination and arrangement of parts, as will be hereinafter more fully described in detail, illustrated in the accompanying drawings which disclose the preferred form of embodiment of the invention to enable those skilled in the art to practice the same, and as brought out in the claims hereunto appended.

In the drawings :Figure 1 is a side elevation of the invention. Fig. 2 is a similar view with the side plate of the slidable member removed. Fig. 3 is a rear end elevation. Fig. 4. is a sectional View on the line 4c4 of Fig. 2. Fig. 5 is a detail perspective view of one of the frictional clamping members. Fig. 6 is a sectional view on the line 6-6 of Fig. 1.

Similar reference characters indicate corresponding parts throughout the several views in the drawings.

In the drawings, there is shown a lifting jack which comprises a standard 8, which is rectangular shape in cross section having opposite smooth surfaces and provided at its lower end with a base or foot 9, to enable the standard to be mounted in a convenient manner upon any suitable foundation. Slidably mounted upon the standard 8, is a supporting member or head 10, which is formed of a hollow casting having detachably mounted at opposite sides thereof side plates 11, the same being correspondingly shaped with respect to the casting and held removably mounted thereon by screw fasteners 12. This casting is provided with registering openings to accommodate the standard 8, and these openings have opposed convex faces 18, to permit free sliding movement of the supporting head upon the standard and to prevent any possibility of the said head becoming wedged or stuck due to excessive friction between the same and the standard.

Projecting into the space or chamber 14, within the supporting head formed by the casting are offset bearing shoulders 15, arranged in superposed relation to each other. Disposed a distance above the lowermost shoulder 15 within the chamber 1a of the supporting head and arranged on opposite sides of the standard 8, are parallel strap links 16, between which are mounted by pivots 17, frictional shoes or runners 18, which latter are adapted to clamp opposed faces of the standard 8, and resting upon the lowermost shoulder 15, is one end of an expansion spring 19, which latter has its opposite end bearing against one of the shoes or runners and this spring is held against displacement by centering lugs 20, and it serves to normally hold the friction shoes in contact with the standard.

Connected to the casting of the head 10,

by a pin 21, is an endless strap forming a loop 22, in which is rotatably mounted an eccentric disk or wheel 23, which latter is eccentrically connected between the strap links 16, by a rock shaft 2d, rigid with the eccentric disk or wheel and provided with a right angular manually operable lever 25, projecting through one side of the supporting head exteriorly thereof and by the manipulation of this lever 25, the frictional Shoes or runners will be actuated to assist in the raising and lowering of the head upon the standard.

At a suitable distance above the strap links 16, and on opposite sides of the standard 8, within the chamber 14, are further parallel strap links 2 1, between which are mounted by pivots 25 slidable friction shoes or runners 26, corresponding to the shoes or runners 18, and contained in the strap links 2 1, are registering elongated slots 27', within which work guide pins 28, projecting from opposite sides of a block 29, integral with the casting of the head. Formed on the uppermost shoulder 15 and the adjacent shoes 26 are centering lugs 30, engaged at opposite ends by a coiled expansion spring 31 which latter normally holds the frictional shoes or runners 26 in engagement or contact with opposite faces of the standard.

Projecting through suitable elongated openings at the rear of the movable head 10", are levers 32 and 33, which latter are integral with and pro ect from the friction shoes 18 and 26 respectively, at one side of the stem, and these levers are operated to permit the lowering of the supporting head 10, upon said standard. It is obvious that the pivots l7. and 25", of the friction shoes 26 and 18 respectively are disposed in different planes with respect to each other to permit the shoes of each pair to move relatively to each other upon the standard when raising or lowering the supporting head.

In operation and to elevate the supporting head 10 upon the standard 8, it is necessary for the operator to manipulate the lever 25, in opposite directions so as to change the position of contact of the friction shoes or runners upon the standard 8, through the medium of the eccentric wheel or disk 23', which upon the lowering of said operable lever pulls upwardly upon the loop 22, thus raising the head and when said; lever is moved in the opposite direction the eccentric disk will advance the friction shoes 18, upon the standard, and the friction shoes 26 will automatically advance when the supporting head is raised by the friction wheel or disk upon the lowering of the manually operable lever. Now to lower the supporting head the operator presses upon the lever 33 against the resistance of the expansion spring 19, to disengage the friction shoes 18, and cause the lowering thereof upon the standard and then pressure is applied to the lever 32 against the resistance of the spring 31, to disengage the friction shoes 26, from the standard and in this manner the supporting head is lowered upon the latter in a step by step operation.

The supporting head is formed with a projecting nose 3% which will prevent an object being lifted or lowered from slipping oil of the supporting head.

In carrying out the invention the lifting jack is not only designed for hoisting and elevating parts, but the same may be utilized for stretching wires or accomplishing a like function.

What is claimed is l. A device of the class described comprising a standard, a supporting head slidably mounted upon said standard, a plurality of clamping means arranged within said head and adapted to frictionally engage the standard and a shiftable eccentric having connection with the head and one of said clamping means for advancing the said head upon the standard.

2. A device of the class described com prising a standard, a supporting head slidably mounted uponsaid standard, a plurality of clamping means arranged within said head and adapted to f'rictionally engage the standard, a shiftable eccentric having connection with the head and one of said clamping means for advancing the said head upon the standard, and spring means acting upon the clamping means to normally hold the latter in positive engagement with the standard.

3. A device of the class described comprising a standard, a supporting head slid ably mounted upon said standard, a plurality of clamping means arranged within said head and adapted to frictionally engage the standard, a shiftable eccentricha-ving connection with the head and one of said clamping means for advancing the said head upon the standard, spring means act ing upon the clamping means to normally hold the latter in positive engagement with the standard, and independent manually operable levers for releasing the clamping means from positive engagement with the standard against the action of the spring means.

4. A device of the class described com prising a standard, amovable member slidably supported upon the standard, superposed frictional shoes engaging opposite faces of the standards, links pivota-lly connecting the said shoes in pairs and disposed at opposite sides of the standard, an eccentric wheel, a strap loop surrounding said eccentric wheel and loosely connected to the movable member, a manually operable lever eccentrically connecting the said eccentric wheel to the links of one pair of friction shoes, means loosely connecting the links of In testimony whereof, we afiiX oui' sig the other pair of friction shoes to the movnatures in presence of two witnesses.

able member, expansion means normally JOHN M. HAWKINS. holding the friction shoes in positive en- SILVESTER E. ADKINS. gagement with the standard, and means for WILLIE O. CALL.

moving one shoe of each pair out of positive 1 Witnesses:

engagement with the standard against the DANIEL MULL,

resistance of the expansion means. GEO. W. PARRISH. 

